No description available.

Made available in DSpace on 2014-10-09T12:52:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:23Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:52:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:23Z (GMT). No. of bitstreams: 0 / Os acidentes causados pelo efeito dominó são dos mais graves ocorridos na indústria química e de processo. Mesmo sendo o potencial destrutivo desses eventos acidentais bastante conhecido, pouca atenção tem sido dada a este problema pela literatura técnica e uma metodologia completa e aprovada para a avaliação quantitativa da contribuição do efeito dominó ao risco industrial ainda não está plenamente desenvolvida. O presente estudo propõe um procedimento sistemático para a avaliação quantitativa do efeito dominó em plantas químicas do ciclo do combustível nuclear. O trabalho é baseado em avanços recentes feitos na modelagem de danos a equipamentos de processo causados por incêndios e explosões devido aos vetores de propagação (radiação de calor, sobrepressão e projeção de fragmentos). Dados disponíveis na literatura técnica e novos modelos de vulnerabilidade deduzidos para diversas categorias de equipamentos de processo foram utilizados no presente trabalho. O procedimento proposto é aplicado a uma área de tancagem típica de uma planta de reconversão situada em um sítio que abriga varias outras instalações do ciclo do combustível nuclear. São analisados os vários eventos iniciadores, seus vetores de propagação, as conseqüências desses eventos e as freqüências associadas ao efeito dominó. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

In this work we develop a Blast-Propellant-Facility integrated analysis study, which evaluates, by using two different approaches, the blast-related impact of an explosive accident of the Space Shuttle during the first ten seconds after launch at Kennedy Space Center. The blast-related risk associated with an explosion at this stage is high because of the quantity of energy involved in both multiple and complex processes. To do this, one of our approaches employed BlastFX®, a software system that facilitates the estimation of the level of damage to people and buildings, starting from an explosive device and rendering results through a complete report that illustrates and facilitates the evaluation of consequences. Our other approaches employed the Hopkinson-Cranz Scaled Law for estimating similar features at a more distant distance and by evaluating bigger amounts of TNT equivalent. Specifically, we considered more than 500 m and 45,400 kg, respectively, which are the range and TNT content limits that our version of BlastFX® can cover. Much research has been done to study the explosion phenomena with respect to both solid and liquid propellants and the laws that underlie the blast waves of an explosion. Therefore our methodology is based on the foundation provided by a large set of literature review and the actual capacities of an application like BlastFX®. By using and integrating the lessons from the literature and the capabilities of the software, we have obtained very useful information for evaluating different scenarios that rely on the assumption, which is largely studied, that the blast waves' behavior is affected by the distance. All of this has been focused on the Space Shuttle system, in which propellant mass represents the source of our analysis and the core of this work. Estimating the risks involved in it and providing results based on different scenarios augments the collective knowledge of risks associated with space exploration.

<p dir="ltr">Blast-induced traumatic brain injury (bTBI) accounts for one-third of traumatic brain injuries (TBI) in soldiers, with chronic effects largely unknown. Electroencephalogram (EEG) signal changes may help predict outcomes like sleep disorders and post-traumatic epilepsy (PTE), which have been reported in rodent bTBI models. Modification of sleep spindles (SSPs), crucial thalamus-cortical signal for sleep transitions, have been linked to PTE and sleep disorders in non-blast TBI, but variability in detection methods affects findings. This study uses an improved SSPs detection algorithm to aim a more rigorous analysis of SSPs characteristics, necessary to understand the sleep disorders and seizure risk 1-month post-bTBI in mice. Following either bTBI or sham (non-blast) treatment, mice underwent a 1-week video-EEG recording, with pentylenetetrazol (PTZ) administered at the end to assess seizure susceptibility. Increased NREM sleep during dark period (hypersomnia) was observed on the first day of recording and a slight reduction in REM sleep was present over the week in both groups, anticipated in bTBI compared to sham. Seizure susceptibility showed no group difference. SSPs density did not differ, but bTBI showed a reduction of SSPs in higher amplitude and frequency range compared to sham. A specific SSP profile correlated with increased seizure susceptibility, though not with REM reduction nor bTBI itself, was identified. In conclusion, video-EEG recording may induce stress, shown by REM reduction in both groups. bTBI appears to increase fragility to stress, likely due to SSPs alterations, both under acute (e.g., first day in new housing) and chronic stress, manifesting as hypersomnia and earlier REM reduction respectively. EEG electrode implantation surgery might also contribute to increased seizure susceptibility. Although the SSP profile is more associated with seizure susceptibility than with bTBI itself, SSP distribution remains altered in bTBI compared to sham reflecting a possible modification of thalamo-cortical connectivity. Further research is needed to confirm SSPs alterations' origins in bTBI.</p>